Button holing system for household sewing machines

ABSTRACT

A controlling device for a buttonholing mechanism in a household sewing machine in which a member having unique construction enabling it to travel in synchronism with the work fabric is linked to a buttonholing unit in the sewing machine to influence the length of the buttonhole. Provision is made for inserting a button in the traveling member for automatically setting the device to influence formation of a buttonhole having a length suitable to accommodate the button. A novel interrelationship between the parts is provided so that an immediate response is attained by the buttonholing unit to signals from the traveling member and as a result buttonholes of very small lengths and circular eyelets may be produced using this mechanism.

PATENTEDAFR 18 1922 SHEET 1 UF 3 INVENTOR. Roger J. Ross 6 2 ATTORNEY WITNESS- [151 3,656,443 [4 1 Apr. 18,1972

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ABSTRACT [73] Assignee: The Singer Company, New York, NY.

PATENTEDAPH I8 1972 SHEET 2 BF 3 Roger J. Ross WITNESSI PATENTEDAPR 18 I972 SHEET 3 [1F 3 INVENTOR. Roger J- Ross BY WVQORNEY WITNESS.

TQM? vg BUTTON HOLING SYSTEM FOR HOUSEHOLD SEWING MACHINES BACKGROUND OF THE INVENTION Mechanisms have been known heretofore which utilize a traveling member responsive to movement of the work fabric to transfer information to buttonhole mechanisms within a sewing machine for determining the length of a buttonhole. Such prior mechanism is disclosed, for instance, in U.S. Pat. No. 3,1 l3,537; however, the disclosure of this patent does not include the means of the present invention for responding to the positioning of a button on the traveling member, or the means for maintaining synchronous movement of the traveling member with the work fabric despite unevenness of the work supporting surface on the machine. In the cited patent, moreover, a limit exists on the length of buttonhole which must be made so that a circular eyelet cannot be made with the mechanism of the cited patent.

SUMMARY OF THE INVENTION This invention provides a control arrangement applicable to a buttonholing mechanism for a household sewing machine such as is disclosed in the U.S. Pat. 3,518,954 of Blackwood et al., July 7, I970. The objects of this invention are attained by a traveling work engaging member slidable on the sewing machine presser foot. The traveling member can accommodate insertion of a button which automatically positions a stop on the traveling member so that a linkage connecting the traveling member with the buttonholing unit will influence formation of a buttonhole having a length suitable for the but ton inserted.

A novel feature of this invention is the provision of separately biased work gripping plungers on the traveling member on the presser foot. These plungers ensure that the work fabric will not shift relatively to the traveling member during the sewing operation.

This invention also includes a modification of the buttonholing unit of the sewing machine in which the cam means which dictates the change of sewing condition between the various portions of a buttonhole is organized so as to eliminate all dwells. The response to signal for change from one portion of a buttonhole to another can thus be immediate, and as a result, buttonholes of very short length including circular eyelets can be stitched using the mechanism of this invention.

DESCRIPTION OF THE DRAWINGS Reference is made to the accompanying drawings of a preferred embodiment of this invention in which:

FIG. 1 represents a perspective view of a sewing machine in phantom lines with a fragment of the sewing machine buttonholing unit, the traveling work engaging member on the presser foot, and the linkage therebetween shown in solid lines.

FIGS. 2A, 2B, 2C and 2D represent four successive stages in the sewing of a buttonhole using the mechanism illustrated in FIG. 1.

FIG. 3 is a perspective view of the traveling work engaging member on the presser foot and a portion of the linkage connected thereto.

FIG. 4 is a disassembled perspective view of the presser foot and traveling member of FIG. 3.

FIG. 5 is a perspective view of the buttonholing unit of the sewing machine showing the linkage connection thereto of this invention in a condition in which the cam means of the buttonhole unit is being driven.

FIG. 6 is a perspective view of a portion of the buttonholing unit of FIG. 5, but shown in a condition in which the drive mechanism for the cam means of the buttonholing unit is rendered ineffective.

FIG. 7 is a rear elevational view of the ratchet wheel of the sewing machine buttonholing unit of FIGS. 5 and 6 showing the cam groove thereof, and

FIG. 8 is an enlarged cross-sectional view of a work engaging plunger taken substantially along line 8-8 of FIG. 3.

Referring to FIG. 1 a sewing machine frame 11 is illustrated in phantom lines. The sewing machine may be made in accordance with the detailed disclosure in the U.S. Pat. No. 3,518,954, July 7, 1970 which is incorporated herein by reference.

Indicated generally at 20 in the drawings is a buttonholing unit which is organized and operates in the same fashion as that disclosed in the above referred to U.S. Pat. No. 3,518,954. Other than a modification of the cam groove arrangement of the buttonholing unit 20, and provision for the connection therewith of a work influenced linkage as will be described hereinbelow, the buttonholing system of this invention can be used with the mechanism as disclosed in the reference patent.

To facilitate an understanding of the present invention, only a brief description of the buttonholing unit 20 will be included herein.

The buttonholing unit is assembled in a bracket 30 attached to the sewing machine 11 and includes a cam disk 31 of which the entire periphery is formed with ratchet teeth 32. The cam disk 31 is joumaled to turn freely in the bracket 30 on a stud shaft 33. A bell crank lever 34 also pivoted on the stud shaft and continuously oscillated during operation of the sewing machine, is connected to a rachet pawl 35 which can reciprocate over and index the ratchet teeth of the cam disk. One face of the cam disk 31 is formed with a cam groove 41 tracked by a follower pin 42 on an operating member 43 for the zigzag and work feeding controls of the sewing machine. A switching device 44 is shown identical to that included in the U.S. Pat. No. 3,518,954 for selectively rendering the operating member effective or ineffective to influence the work feed mechanism of the sewing machine.

The cam groove 41 of the present invention differs from that disclosed in U.S. Pat. No. 3,518,954 in that the cam groove is divided into six equally spaced segments of which every other segment 48, is formed with the radius of the cam groove gradually increasing considered in the direction of relative movement of the follower pin 42 along the groove and alternate segments 49 are formed with the radius of the cam groove gradually decreasing. There are no dwell portions of uniform radius in the cam groove 41 as exist in the U.S. Pat.

No. 3,518,954, nor are there any interruptions in the ratchet teeth.

Referring to FIGS. 5 and 6, a bell crank lever 50 fulcrummed on a pin 51 in the bracket 30 is biased in a clockwise direction as viewed in FIG. 6 by a spring 52. Pivotally secured as at 53 to the bell crank lever 50 is a pawl throw-out arm 54 formed with a lateral off-set 55 and with a finger 56 underlying the pawl 35. A spring 57 acting between the lever 50 and the pawl throw-out arm 54 biases the throw-out arm downwardly.

Projecting laterally from adjacent to the periphery of the cam disk 31 are six equally spaced pins 60 which serve when the cam disk is turned by the pawl 35 to move successively into engagement with the pawl throw-out arm 54 to elevate the arm and with it the pawl 35 out of operative contact with the ratchet wheel. The pins 60 are located relatively to the cam groove segments 48 and 49 each to disable the pawl when the cam follower pin 42 reaches a juncture between adjacent segments 48 and 49 of the cam groove.

In order to re-engage the pawl 35 on the ratchet teeth 32, it is necessary that the bell crank lever 50 must be turned counterclockwise as viewed in FIGS. 5 and 6 so as to draw the throw-out arm 54 to the left and position the lateral offset 55 beyond the pin 60 which has just elevated the throw-out arm. As shown in FIG. 5, this shift of the throw-out arm will cause the arm to fall under the action of the spring 57 allowing the pawl 35 to return to effective position.

As shown in FIGS, 1 and 5, a push button constrained in a block 71 adjacent to the buttonholing unit 20 is pivotally connected at 72 to a bell crank 73 fulcrummed on the block 71. The free arm 74 of the bell crank engages the bell crank lever 50 so that depression of the push button 70 can operate to return the pawl 35 to an effective position.

As shown in FIG. 1, the bell crank lever is provided with a fastening screw 79 by which it is connected to a linkage indicated generally at 80 by which an impulse related to the movement of work fabric being stitched may be transmitted to the buttonholing unit to return the pawl to effective position.

As illustrated in FIGS. 1, 3 and 4, the linkage 80 includes an extension 81 secured by the screw 79 to the bell crank lever 50, and a link 82 pivoted at 83 to the extension and pivoted at 84 to a lever 85 situated generally transversely across the sewing machine bracket arm. The lever 85 is fulcrummed on a pin 86 fastened in a block 87 which is secured in the sewing machine by a screw 88 which passes through a slot 89 in the block so that the linkage may be adjusted to account for differences in tolerances of the various parts. A spring wire clip 90 pivotally joins the lever 85 with a lever arm 91 extending from a rock shaft 92 journaled vertically in the sewing machine bracket arm. A rock arm 93 clamped beneath the sewing machine bracket arm terminates in a slot 94 entered by the upstanding arm 95 of a lever 96 fulcrummed on a pin 97 pivoted in the shank 98 of a presser foot 99. The shank 98 is adapted to be secured by conventional means to a regular sewing machine presser bar.

As shown in FIGS. 3 and 4, a presser foot sole plate 100 preferably formed with spaced parallel blades 101 extending in the direction of work feed of the sewing machine is secured to the shank 98 by a pivot pin 102. A rearwardly extending support finger 103 from the presser foot sole plate accommodates a spring 104 constrained on an anchor pin 105 protruding from the shank 98 which serves to bias the forward or toe portion of the presser foot sole plate downwardly.

Slidable along the presser foot sole plate blades 101 in the direction of work feed is a traveling work engaging assembly consisting of a sheet metal plate formed with an access opening 111 exposing an area for the formation of a buttonhole, which is straddled by the sole plate blades 101. Along one side, the plate is formed with an upturned and inturned flange 112 which embraces one of the sole plate blades 101. Along the other side, the plate 110 is formed with an upwardly offset step 113 which abuts the other one of the sole plate blades but which terminates in an upstanding flange 114 spaced from the sole plate.

Secured to the step 113 by screws 115 is a bent sheet metal strip 116 having a lip 117 which overhangs the presser foot sole plate blade 101 and locks the traveling member thereon. One extremity of the strip 116 is formed with a pair of bent abutment projections 118 providing a seat for reception of a button. Slidable beneath the strip 116 is a block 119 carrying a button engaging projection 120 which extends upwardly through a slot 121 in the strip and which in cooperation with the projections 118 can accommodate a selected button therebetween A clamp screw 122 also passing through the slot 121 serves to clamp the projection 120 in selected position depending upon the size of the button placed between the projections 120, 118.

The block 119 also carries a fastening screw 125 which extends through communicating clearance slots 126 and 127 in the strip 116 and in the plate 110, respectively. A cam element 130 is secured by the fastening screw 125 to the block 119. The cam element 130 is thus positioned along the traveling work engaging assembly by the block 119 and is positioned to engage the free extremity of the lever 96 on the presser foot to actuate the linkage 80.

Identical spring loaded work engaging plungers are carried at the front and rear of the traveling sheet metal plate 110. The work engaging lower extremity 151 of each plunger which may be formed of rubber, roughened metal, or other high friction material, extends through an aperture 152 in the plate 110. An annular flange 153 on the plunger limits movement thereof through the aperture 152. Secured as by welding to the sheet metal plate 110 concentric with the aperture 152 is an externally threaded tube 154 into which the annular flange 153 fits. A coil spring 155 is constrained against the annular flange 153 of the plunger to bias the plunger downwardly by a cap 156 which is threaded onto the tube 154. An aperture 157 in the cap accommodates the top of the plunger.

When the buttonholing system of this invention is applied to a sewing machine, the linkage 80 is secured permanently to the sewing machine and when it is desired to sew a buttonhole, the presser foot assembly as shown in FIG. 3 is secured to the sewing machine presser bar in place of a conventional presser foot with care being taken that the upstanding arm 95 of the lever 96 on the presser foot is engaged in the slot 94 of the rock arm 93.

The conventional zig-zag controls of the sewing machine are then set to provide a plain zig-zag stitch at slightly less than half of the total possible width or bight of which the sewing machine is capable of zig-zag stitching and the switching device 44 is turned to couple the buttonholing unit operating member 43 to the sewing machine work feeding mechanism.

A button 160 of the size for which a buttonhole is to be sewn is placed between the projections 118 and 120, and the slide block 119 is moved until the button touches both the projections 118 and 120 after which the slide block is secured to the traveling assembly by the clamp screw 122.

The work fabric is placed beneath the sheet metal plate 110 of the traveling work engaging assembly with the desired location of the buttonhole disposed in the access opening 111. The front edges of the parallel blades 101 of the presser foot are then aligned with indicia on the plate 110 and the machine is ready to begin stitching the buttonhole.

The push button 70 is depressed to shift the throw-out arm 54 to the left as viewed in the drawings causing it to drop alongside the pin 60 which had been holding it elevated. This lowers the pawl 35 and when the machine is operated, one segment 48 of the cam groove 41 will traverse the follower pin 42 gradually shifting the operating member 43 to form one end of a buttonhole as illustrated in FIG. 2A. The next succeeding pin 60 will then elevate the throw-out arm 54 raising the pawl 35 to ineffective position and the machine will continue to form one side of the buttonhole as shown in FIG. 2B until the free extremity 135 of the lever 96 on the presser foot strikes and is shifted by the cam element 130.

TI-Ie linkage 80 will then transmit this signal to the throwout arm 54 again withdrawing the arm to the left of the pin 60 as viewed on the drawings and permitting the pawl 35 to drop into effective driving relation with the ratchet wheel. Subsequent traverse of a cam groove segment 49 relatively to the follower pin 42 will cause the stitching of the opposite end of the buttonhole as shown in FIG. 2C. A succeeding pin 60 on the cam disk will then elevate the arm 54 and deactivate the pawl 35 leaving the machine in a position of adjustment as to stitch the remaining side of the buttonhole as shown in FIG. 2D. When stitching of the last side of the buttonhole closes with the beginning end of the buttonhole, operation of the machine is stopped and the buttonhole sewing is completed.

Having thus described the nature of the invention, what I claim herein is:

l. A presser device for use on a sewing machine having a buttonhole producing mechanism therein, said presser device comprising a presser foot adapted to be secured to a sewing machine presser bar, a work engaging plate slidably constrained on said presser foot, button embracing projections carried on said plate including a projection fixed on said plate and another projection shiftably supported on said plate selectively to accommodate any one of a range of different size buttons therebetween, cam means associated and movable with said shiftably supported projection on said plate, and linkage means carried by said presser foot and operatively engageable with said cam means for influencing the buttonholing mechanism in a sewing machine to which the presser device is secured so as to produce a buttonhole having a length which will accommodate a button embraced between said projectrons.

2. A presser device for use on a sewing machine having a buttonhole producing mechanism as set forth in claim 1 in which work engaging plungers are carried by said work engaging plate, one at each side of said presser foot, each of said plungers being shiftably supported for limited movement substantially perpendicular to the work, and spring means acting between said plate and each of said plungers for biasing said plungers toward engagement with the work.

3. An automatic buttonhole mechanism for a sewing machine having a zig-zag stitching mechanism and a reversible work feeding mechanism, said buttonhole mechanism comprising in combination a pattern cam means operatively connectable to said zig-zag stitching and work feeding mechanisms, said pattern cam means having alternate cam segments for forming by use of one segment, a buttonhole end terminating in a condition for side stitching along one side of the finished buttonhole, and for forming by use of a succeeding segment a buttonhole end terminating in a condition for side stitching along the opposite side of the buttonhole, means operated continuously during operation of said sewing machines for driving said pattern cam means, a throw-out element for said pattern cam operating means, means carried by said pattern cam means and effective after response to each successive segment of said pattern cam for rendering said throwout means effective, sensing means carried by said sewing machine in engagement with and responsive to movement of work fabric by said sewing machine work feeding mechanism, and linkage means operatively connecting said sensing means with said throw-out element for rendering said throw-out element ineffective.

4. An automatic buttonhole mechanism as set forth in claim 3 in which said alternate segments of said pattern cam means are contiguous without dwell portions therebetween and are formed each to influence of a round buttonhole end, whereby the mechanism is capable of producing stitched circular eyelets.

5. An automatic buttonhole mechanism as set forth in claim 3 in which said pattern cam means comprises a pattern cam disk formed with a cam groove of which the radius gradually increases along every other segment and decreases along alternate segments, and in which said pattern cam driving means comprises ratchet teeth formed continuously about the periphery of said pattern cam disk and an operating pawl driven by said sewing machine relatively to such ratchet teeth.

6. An automatic buttonhole mechanism as set forth in claim 5 in which said throw-out element for said pattern cam drive means is interposed between said ratchet teeth and said pawl, in which the means for rendering said throw-out means effective, comprises a projection on said pattern cam for shifting said throw-out element radially of said pattern cam to separate said pawl from said ratchet teeth, and in which said linkage means for rendering said throw-out means ineffective includes means for shifting said throw-out element tangentially of said pattern wheel out of cooperation with said projection. 

1. A presser device for use on a sewing machine having a buttonhole producing mechanism therein, said presser device comprising a presser foot adapted to be secured to a sewing machine presser bar, a work engaging plate slidably constrained on said presser foot, button embracing projections carried on said plate including a projection fixed on said plate and another projection shiftably supported on said plate selectively to accommodate any one of a range of different size buttons therebetween, cam means associated and movable with said shiftably supported projection on said plate, and linkage means carried by said presser foot and operatively engageable with said cam means for influencing the buttonholing mechanism in a sewing machine to which the presser device is secured so as to produce a buttonhole having a length which will accommodate a button embraced between said projections.
 2. A presser device for use on a sewing machine having a buttonhole producing mechanism as set forth in claim 1 in which work engaging plungers are carried by said work engaging plate, one at each side of said presser foot, each of said plungers being shiftably supported for limited movement substantially perpendicular to the work, and spring means acting between said plate and each of said plungers for biasing said plungers toward engagement with the work.
 3. An automatic buttonhole mechanism for a sewing machine having a zig-zag stitching mechanism and a reversible work feeding mechanism, said buttonhole mechanism comprising in combination a pattern cam means operatively connectable to said zig-zag stitching and work feeding mechanisms, said pattern cam means having alternate cam segments for forming by use of one segment, a buttonhole end terminating in a condition for side stitching along one side of the finished buttonhole, and for forming by use of a succeeding segment a buttonhole end terminating in a condition for side stitching along the opposite side of the buttonhole, means operated continuously during operation of said sewing machines for driving said pattern cam means, a throw-out element for said pattern cam operating means, means carried by said pattern cam means and effective after response to each successive segment of said pattern cam for rendering said throw-out means effective, sensing means carried by said sewing machine in engagement with and responsive to movement of work fabric by said sewing machine work feeding mechanism, and linkage means operatively connecting said sensing means with said throw-out element for rendering said throw-out element ineffective.
 4. An automatic buttonhole mechanism as set forth in claim 3 in which said alternate segments of said pattern cam means are contiguous without dwell portions therebetween and are formed each to influence formation of a round buttonhole end, whereby the mechanism is capable of producing stitched circular eyelets.
 5. An automatic buttonhole mechanism as set forth in claim 3 in which said pattern cam means comprises a pattern cam disk formed with a cam groove of which the radius gradually increases along every other segment and decreases along alternate segments, and in which said pattern cam driving means comprises ratchet teeth formed continuously about the periphery of said pattern cam disk and an operating pawl driven by said sewing machine relAtively to such ratchet teeth.
 6. An automatic buttonhole mechanism as set forth in claim 5 in which said throw-out element for said pattern cam drive means is interposed between said ratchet teeth and said pawl, in which the means for rendering said throw-out means effective, comprises a projection on said pattern cam for shifting said throw-out element radially of said pattern cam to separate said pawl from said ratchet teeth, and in which said linkage means for rendering said throw-out means ineffective includes means for shifting said throw-out element tangentially of said pattern wheel out of cooperation with said projection. 